That just benefits vertical integration. Amazon would pay less taxes in Amazon basics than third party goods. What you really want is a VAT. You're only taxed on the value add of your product. It's widely regarded as the most efficient tax and the US is one of the only countries that doesn't use it.
VAT does capture B2B transactions. That's what makes it different from a sales tax. I'm pretty sure that you already have to pay VAT when buying online ads.
Even if it does mean less restaurants and less eating out, there is nothing inherently more unfair about it.